Poly(vinylpyrrolidone) complexed with iodine (polyvinylpyrrolidone-iodine complex) is widely recognized for its anti-microbial properties. Since the iodine is tightly complexed, germicidal properties can be obtained without the toxicity or staining concerns associated with preparations containing elemental iodine. Its use in medicine and veterinary medicine as an anti-infective is widely recognized, where the complex is also known as “povidone-iodine”.
Efforts were made to combine polyvinylpyrrolidone-iodine complex with polymer and copolymer products by radiation-grafting or by solution or dispersion coatings. See, e.g., JP2003095277A.
A polymer characterized as comprising a backbone and bonded thereto a polymeric pendant group was disclosed. However, the polyvinylpyrrolidone-iodine complex cannot be melt extruded alone. See, e.g., WO 2000064264.
Polyvinylpyrrolidone-iodine complex is a water-soluble brown powder with a melting point of about 300° C. with decomposition. The heat and shear of melt extrusion results in thermal degradation. Thus, polyvinylpyrrolidone-iodine complex by itself is not sufficiently thermally stable to extrude. While absorption of water lowers the extrusion temperature of polyvinylpyrrolidone-iodine complex significantly, the presence of water during thermal extrusion is undesirable, causing a number of problems such as volatiles, film bubbles, etc.
Films containing polyvinylpyrrolidone-iodine complex have only been made by solution casting. The solution-cast film can then be “graft-polymerized by radiation” to one side (or potentially both sides) of a film from which products such as bags or pouches can be fabricated. If bags are to be made by melt sealing the laminated film conventionally, the polyvinylpyrrolidone-iodine complex may be restricted to the outside of the bag only.
It is desirable to extend and simplify the inclusion of the polyvinylpyrrolidone-iodine complex into a polymer or copolymer to provide melt-extrudable composition. Films, fibers, and other shaped articles with microbiocidal properties could be provided by melt blending the polymer or copolymer with the polyvinylpyrrolidone-iodine complex followed by extrusion. Melt extrudable films provide a significant economic improvement over solution-cast films. The invention provides such compositions, processes, and products.